Structural characterization of the RNA chaperone Hfq from the nitrogen-fixing bacterium Herbaspirillum seropedicae SmR1

► The first Hfq structure from a Gram negative diazotrophic bacterium. ► A novel π-π staking intra-subunit interaction of two histidine residues was revealed. ► The SAXS envelope suggests that the protein has the same folding in solution.